Origin and Habitat: Lophophora lutea (=Lophophora diffusa) is the southernmost population of Lophophora endemic of the of the state of Querétaro, México it grows only in a small area in the hight desert in a valley between Vizarron, Bucareli, and Toliman (Extent of occurrence about 300 km²). L. diffusa occurs at the south end of the range of the genus.Altitude: It grows at an elevations of 1,300 to 1,800 metres above sea level.Habitat and Ecology: Driest and stoniest desert Xerophytic shrubland, on calcareous soils where the soil is deep enough to allow the tuberous root to grow. L. diffusa grows mainly beneath the canopy of some locally dominant shrub and possible nurse plant (e.g. Larrea tridentata and Acacia sororia). The species is threatened by illegal collecting and use by indigenous people for medicine, and by collectors for ornamental trade.

Description:Lophophora lutea (= Lophophora diffusa) is a globular spineless cactus with large tap root. Solitary or forming variable stemmed clumps with few stems or sometime large mounded group with several heads. This is the more primitive species of Lophophora. It is rare in cultivation:Stem: 2-7 cm tall, 5-12 cm in diameter (some population have larger stems up to 20-25 cm in diameter), yellow-green or grey-green, usually lacking well-defined ribs and furrows.Ribs: 5 to 13 the podaria are rarely elevated, wavy, broad and flat.Areoles: With tufts of hairs that usually spread unequally on the prominent podaria.Flowers: Commonly whitish to yellowish-white, 1,5-3 centimetres in diameter.Note:Lophophora lutea (= Lophophora diffusa) is geographically isolated, but questionably distinct from Lophophora williamsii.

Subspecies, varieties, forms and cultivars of plants belonging to the Lophophora diffusa group

Lophophora diffusa var. koehresiiŘíha: This is probably the smallest Lophophora. It has big pale pink flowers with darker midstrip. Stem characteristically dark green coloured and the ribs are more strongly in relief.

Lophophora diffusa subs. kubesaeHalda, Kupčák & Malina: The particularity of this subspecies will be revealed only in older specimens that are larger in size and tend to form large multi-headed heaps, up to 1,5 mt in diameter.

Cultivation and Propagation: Slow growing Requires half shade in summer, full sun the rest of the year.Grow it in a narrow and deep container to accommodate the tap root, they are very rot prone, so use highly gritty compost with much drainage.Waterings should be rather infrequent to keep the plant compact and not to become excessively elongated and unnatural in appearance, watering it properly is often difficult because this plant tends to crack open or rot if over-watered. The fact that the plant retracts into the soil and assume a grey-green colouring between watering, is perfectly natural and doesn’t cause any damage.Like other arid zone cacti, they require a dry and cool over-wintering otherwise they may succumb to rot. It also promotes flowering. Assure a good ventilation.Propagation: Seeds. Seed should be sown in spring in sterile cacti mix. Cover with a humidity dome or plastic wrap and leave in a warm spot in 50-75% shade. Fluctuating temperatures are best (ie. high day temperature and low night temperature) as they simulate the desert environment.Keep constantly humid as seedlings cannot survive if to dry. Seedlings will emerge in 7-21 days and can be grown in the same environment for a number of months. Mulch with thin layer of small quartz gravel (1-2mm diameter) this helps them stay upright, hinders algae growth and regulates moisture. As they get older the watering can become less frequent. Potting up can be done when 5-10mm in diameter.